I'm making the solar-filter cell for the 37" right now, and I would like some input from the list: In white-light solar mode, the big scope will have a 12" off-axis mask to accomodate the filter. I had planned on using Baader material, based on my own experience with it. (This mask can also be used without the filter at night, for unobstructed viewing when seeing won't support full-aperture). This is the groups last chance to change my mind, if anyone knows of a better filter material. We can get a glass filter if it truly yields a better image than Baader material. Let me know! Thanks Chuck